Low complexity adaptive filter

Abstract

An interim filter determined for a previous series of video blocks can be applied to a current series of video blocks to determine an interim filter map for the current series of video blocks. Based on the interim filter map, a decoding filter can be determined. By applying the decoding filter to the current series of video blocks, a decoding filtering map can be determined. Based on CUs identified as having filtering off by the decoding filtering map, an interim filter for the current series of video blocks can be determined. The decoding filter and decoding filtering map can be transmitted to a decoder, while the interim filter and interim filter map may not be transmitted to a decoder. The interim filter for the current series of video blocks can be used to generate an interim filter map for a next series of video blocks.

1 . A method of video coding comprising:
 determining a first filter for a first series of video blocks;   determining a first interim filter for the first series of video blocks, wherein the first interim filter is determined for coded units of the first series of video blocks not to be filtered by the first filter;   applying the first interim filter to a second series of video blocks to determine an interim filter map, wherein the interim filter map identifies a first set of coded units of the second series of video blocks and a second set of coded units of the second series of video blocks;   determining a second filter for the second series of video blocks, wherein the second filter is determined for the first set of coded units of the second series of video blocks;   applying the second filter to the coded units of the second series of video blocks to determine a decoding filter map, wherein the decoding filter map identifies coded units of the second series of video blocks to be filtered by the second filter and coded units of the second series of video blocks not to be filtered by the second filter;   determining a second interim filter for the coded units of the second series of video blocks not to be filtered by the second filter.   
     
     
         2 . The method of  claim 1 , wherein the first interim filter is different than the first filter. 
     
     
         3 . The method of  claim 1 , wherein information identifying the first filter, the second filter, and the decoding filter map is included in an encoded bitstream. 
     
     
         4 . The method of  claim 3 , wherein information identifying the first interim filter, the second interim filter, and the interim filter map is not included in the encoded bitstream. 
     
     
         5 . The method of  claim 1 , wherein the first set of coded units are coded units improved by application of the first interim filter. 
     
     
         6 . The method of  claim 1 , wherein the second set of coded units are coded unit not improved by application of the first interim filter. 
     
     
         7 . The method of  claim 1 , wherein determining the second filter comprises analyzing an auto-correlations and a cross-correlations between a filtered version of the first set of coded units and an original version of the first set of coded units. 
     
     
         8 . The method of  claim 1 , wherein the first series of video blocks is a slice of a video frame. 
     
     
         9 . A video coding device comprising:
 a prediction unit that generates a first series of video blocks and a second series of video blocks;   a filter unit that
 determines a first filter for the first series of video blocks; 
 determines a first interim filter for the first series of video blocks, wherein the first interim filter is determined for coded units of the first series of video blocks not to be filtered by the first filter; 
 applies the first interim filter to the second series of video blocks to determine an interim filter map, wherein the interim filter map identifies a first set of coded units of the second series of video blocks and a second set of coded units of the second series of video blocks; 
 determines a second filter for the second series of video blocks, wherein the second filter is determined for the first set of coded units of the second series of video blocks; 
 applies the second filter to the coded units of the second series of video blocks to determine a decoding filter map, wherein the decoding filter map identifies coded units of the second series of video blocks to be filtered by the second filter and coded units of the second series of video blocks not to be filtered by the second filter; 
 determines a second interim filter for the coded units of the second series of video blocks not to be filtered by the second filter. 
   
     
     
         10 . The video coding device of  claim 9 , wherein the first interim filter is different than the first filter. 
     
     
         11 . The video coding device of  claim 9 , wherein information identifying the first filter, the second filter, and the decoding filter map is included in an encoded bitstream. 
     
     
         12 . The video coding device of  claim 11 , wherein information identifying the first interim filter, the second interim filter, and the interim filter map is not included in the encoded bitstream. 
     
     
         13 . The video coding device of  claim 9 , wherein the first set of coded units are coded units improved by application of the first interim filter. 
     
     
         14 . The video coding device of  claim 9 , wherein the second set of coded units are coded unit not improved by application of the first interim filter. 
     
     
         15 . The video coding device of  claim 9 , wherein the filter unit determines the second filter by analyzing an auto-correlations and a cross-correlations between a filtered version of the first set of coded units and an original version of the first set of coded units. 
     
     
         16 . The video coding device of  claim 9 , wherein the first series of video blocks is a slice of a video frame. 
     
     
         17 . An apparatus for coding video, the apparatus comprising:
 means for determining a first filter for a first series of video blocks;   means for determining a first interim filter for the first series of video blocks, wherein the first interim filter is determined for coded units of the first series of video blocks not to be filtered by the first filter;   means for applying the first interim filter to a second series of video blocks to determine an interim filter map, wherein the interim filter map identifies a first set of coded units of the second series of video blocks and a second set of coded units of the second series of video blocks;   means for determining a second filter for the second series of video blocks, wherein the second filter is determined for the first set of coded units of the second series of video blocks;   means for applying the second filter to the coded units of the second series of video blocks to determine a decoding filter map, wherein the decoding filter map identifies coded units of the second series of video blocks to be filtered by the second filter and coded units of the second series of video blocks not to be filtered by the second filter;   means for determining a second interim filter for the coded units of the second series of video blocks not to be filtered by the second filter.   
     
     
         18 . The apparatus of  claim 17 , wherein the first interim filter is different than the first filter. 
     
     
         19 . The apparatus of  claim 17 , wherein information identifying the first filter, the second filter, and the decoding filter map is included in an encoded bitstream. 
     
     
         20 . The apparatus of  claim 19 , wherein information identifying the first interim filter, the second interim filter, and the interim filter map is not included in the encoded bitstream. 
     
     
         21 . The apparatus of  claim 17 , wherein the first set of coded units are coded units improved by application of the first interim filter. 
     
     
         22 . The apparatus of  claim 17 , wherein the second set of coded units are coded unit not improved by application of the first interim filter. 
     
     
         23 . The apparatus of  claim 17 , wherein determining the second filter comprises analyzing an auto-correlations and a cross-correlations between a filtered version of the first set of coded units and an original version of the first set of coded units. 
     
     
         24 . The apparatus of  claim 17 , wherein the first series of video blocks is a slice of a video frame. 
     
     
         25 . A computer program product comprising a computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors of a device for coding video data to:
 determine a first filter for a first series of video blocks;   determine a first interim filter for the first series of video blocks, wherein the first interim filter is determined for coded units of the first series of video blocks not to be filtered by the first filter;   apply the first interim filter to a second series of video blocks to determine an interim filter map, wherein the interim filter map identifies a first set of coded units of the second series of video blocks and a second set of coded units of the second series of video blocks;   determine a second filter for the second series of video blocks, wherein the second filter is determined for the first set of coded units of the second series of video blocks;   apply the second filter to the coded units of the second series of video blocks to determine a decoding filter map, wherein the decoding filter map identifies coded units of the second series of video blocks to be filtered by the second filter and coded units of the second series of video blocks not to be filtered by the second filter;   determine a second interim filter for the coded units of the second series of video blocks not to be filtered by the second filter.   
     
     
         26 . The computer program product of  claim 25 , wherein the first interim filter is different than the first filter. 
     
     
         27 . The computer program product of  claim 25 , wherein information identifying the first filter, the second filter, and the decoding filter map is included in an encoded bitstream. 
     
     
         28 . The computer program product of  claim 27 , wherein information identifying the first interim filter, the second interim filter, and the interim filter map is not included in the encoded bitstream. 
     
     
         29 . The computer program product of  claim 25 , wherein the first set of coded units are coded units improved by application of the first interim filter. 
     
     
         30 . The computer program product of  claim 25 , wherein the second set of coded units are coded unit not improved by application of the first interim filter. 
     
     
         31 . The computer program product of  claim 25 , wherein determining the second filter comprises analyzing an auto-correlations and a cross-correlations between a filtered version of the first set of coded units and an original version of the first set of coded units. 
     
     
         32 . The computer program product of  claim 25 , wherein the first series of video blocks is a slice of a video frame.